Ultrahigh Q surface lattice resonance supported by a U-shaped resonant ring nanoarray

Area of Science:

• Plasmonics and Nanophotonics
• Metamaterials and Metasurfaces
• Electromagnetism and Optics

Background:

• Surface lattice resonance (SLR) enables enhanced light-matter interactions in periodic nanostructures.
• Achieving ultrahigh Q-factors in SLRs is crucial for sensitive sensing and advanced optical devices.
• Conventional SLRs often face limitations in Q-factor enhancement due to radiative losses.

Purpose of the Study:

• To demonstrate an ultrahigh Q-factor SLR using a U-shaped split ring resonator (U-SRR) array.
• To investigate the physical mechanisms responsible for the enhanced Q-factor in the U-SRR-based SLR.
• To explore the potential of this platform for future nanoscale device applications.

Main Methods:

• Fabrication and characterization of a U-shaped split ring resonator (U-SRR) array.
• Numerical simulations (e.g., Finite-Difference Time-Domain) to model the optical response.
• Semi-analytical analysis to understand the underlying physical principles and radiation suppression mechanisms.

Main Results:

• Achieved an ultrahigh Q-factor for SLR, exceeding 10^4.
• Demonstrated a high transmission resonance amplitude (up to 0.8) concurrently with the ultrahigh Q-factor.
• Identified dual radiation suppression mechanisms: reduction of dipole moment and excitation of in-plane quadrupole, unique to the U-SRR geometry.

Conclusions:

• The U-SRR array provides an effective platform for achieving ultrahigh Q-factor SLRs.
• The unique geometry of U-SRRs offers enhanced radiation suppression beyond conventional SLR.
• The proposed platform holds promise for developing highly flexible and advanced nanoscale optical devices.